package threading;

public class ThreadDemo3_19_2 {

        // 计数器
        private static volatile int COUNTER = 0;
        // 定义一个单独的锁对象
        private static Object lock = new Object();

        public static void main(String[] args) {
            // 创建三个线程，并指定线程名，每个线程名分别用A,B,C表示
            Thread t1 = new Thread(() -> {
                // 循环10次
                for (int i = 0; i < 10; i++) {
                    // 执行的代码加锁
                    synchronized (lock) {
                        // 每次唤醒后都重新判断是否满足条件
                        // 每条线程判断的条件不一样，注意线程t1,t2
                        while (COUNTER % 3 != 0) {
                            try {
                                // 不满足输出条件时，主动等待并释放锁
                                lock.wait();
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                        // 满足输出条件，打印线程名，每条线程打印的内容不同
                        System.out.print(Thread.currentThread().getName());
                        // 累加计数
                        COUNTER++;
                        // 唤醒其他线程
                        lock.notifyAll();
                    }
                }
        }, "A");

        Thread t2 = new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                synchronized (lock) {
                    while (COUNTER % 3 != 1) {
                        try {
                            lock.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.print(Thread.currentThread().getName());
                    COUNTER++;
                    lock.notifyAll();
                }
            }
        }, "B");

        Thread t3 = new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                synchronized (lock) {
                    while (COUNTER % 3 != 2) {   //这个条件保证了C 是在打印B之后的，
                                                 // 唤醒完全部线程之后，由于不满足条件又会进入wait状态
                        try {
                            lock.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }

                    // 换行打印
                    System.out.println(Thread.currentThread().getName());
                    COUNTER++;
                    lock.notifyAll();
                }
            }
        }, "C");

        // 启动线程
        t1.start();
        t2.start();
        t3.start();
    }
}


class Demo {
    private static Object locker1 = new Object();
    private static Object locker2 = new Object();
    private static Object locker3 = new Object();

    public static void main(String[] args) throws InterruptedException {
        Thread t1 = new Thread(() -> {
            try {
                for (int i = 0; i < 10; i++) {
                    synchronized (locker1) {
                        locker1.wait();
                    }
                    System.out.print("A");
                    synchronized (locker2) {
                        locker2.notify();
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });

        Thread t2 = new Thread(() -> {
            try {
                for (int i = 0; i < 10; i++) {
                    synchronized (locker2) {
                        locker2.wait();
                    }
                    System.out.print("B");
                    synchronized (locker3) {
                        locker3.notify();
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });

        Thread t3 = new Thread(() -> {
            try {
                for (int i = 0; i < 10; i++) {
                    synchronized (locker3) {
                        locker3.wait();
                    }
                    System.out.println("C");
                    synchronized (locker1) {
                        locker1.notify();
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        });
        t1.start();
        t2.start();
        t3.start();

        Thread.sleep(1000);

        // 从线程 t1 启动
        synchronized (locker1) {
            locker1.notify();
        }
    }
}
